docs: def _augment_node(node: BaseEntity) -> BaseEntity:
      """Add the SHA-512 identifier to a node's dictionary."""
      rv = node.copy()
      rv['id'] = node.as_sha512()
      rv['bel'] = node.as_bel()
      for m in chain(node.get(MEMBERS, []), node.get(REACTANTS, []), node.get(PRODUCTS, [])):
          m.update(_augment_node(m))
      return rv